Manufacture of textile materials



Patented Mar. 5, 1940 UNITED STATES PATENT I OFFICE MANUFACTURE OF TEXTILE MATERIALS No Drawing. Application October 19, 1936, Se-

rial No. 106,496. In Great 4 Claims.

The present invention relates to an improved process for the multiplying of textile fabrics, and to products obtained thereby. While applicable to textile fabrics of various kinds, it is of particular interest when used with cotton and linen fabrics.

The usual agents employed for doubling fabrics are rubber, synthetic resins and cellulose derivatives, the last being of the kind soluble in organic solvents and possessing thermoplastic properties. These cellulose derivatives are employed in solution in organic solvents, which for the sake of economy and safety must be recovered in suitable apparatus and safeguarded against risk of fire.

The object of this invention is to provide an improved process for multiplying textile fabrics. A further object is to produce better multiplied textile fabrics. A furtherobject is to provide a process for multiplying textile fabrics which does not make use of the ordinary organic solvents. A further object is to produce multiplied fabrics which are unaffected by organic solvents. Further objects of this invention will be apparent or disclosed in the following description.

These objects are obtained by the use of solutions of cellulose derivatives of the type insoluble in the usual organic solvents and in water, but

soluble in dilute aqueous caustic soda, either immediately at ordinary temperature, or after subjection of their suspensions in dilute. aqueous caustic soda to freezing and subsequent thawing to ordinary temperature, or by employment of one or other of the processes described in U. S. Patents Nos. 2,036,257 and 2,046,174.

According to the present invention a fabric is coated with a comparatively strong solution in dilute aqueous caustic soda of a cellulose derivative of the kind described, and is caused by pressure to adhere by its coated surface or surfaces to a layer or layers of a separate fabric, whereupon the assembly is treated with a coagulating agent to precipitate the. cellulose derivative, washed, and dried.

The cellulose derivatives employed are ethers and esters characterised by a low degree of etheriflcation, and may be produced according to methods described in U. S. Patents Nos. 2,036,257, 2,046,174 and 2,042,484 and British specification No. 416,590. Among the low-substituted derivatives having the desired properties may be mentioned glycol cellulose, methyl and ethyl cellulose, cellulose sulphate and phosphate, hydroxypropyl cellulose and glyceryl cellulose.

Cellulose derivatives of the kind described are Britain October 24,

most easily brought into solution in caustic soda I solutions of some concentration which usually lies between 5% and 10%, and are less easily dissolved in solutions of other concentrations. Moreover, even when the optimum concentration of caustic soda is used the amount of the cellulose derivative that can be dissolved to form a substantially complete solution is limited. For the purposes of the present invention, a solution of more than 5 parts of the cellulose derivative per parts of solution may be regarded as a comparatively strong solution. The viscosity of a solution containing a given concentration of the cellulose derivative may vary considerably according to the method of production of the cellulose derivative.

If desired, the material obtained by the application of pressure from the thicknesses of fabric and the interposed cementing solution may be dried at a raised temperature before it is subjected to the action of the precipitating medium. In the case of glycol cellulose, for instance, we have found that this is particularly desirable when the glycol cellulose is of the kind yielding a solution of comparatively low viscosity, such as a material having a viscosity of about 5-30 0. g. s. imits when determined at 20 C. in a solution made by subjecting 7 parts of glycol cellulose in 93 parts of 7.5% caustic soda solution to a temperature such that crystals of ice begin to appear and then allowing the mass to rise to room temperature. We prefer, however, to employ glycol cellulose solutions having a viscosity of about 30 to c. g. s. units, in which case no intermediate heat treatment is necessary.

In one method of putting the invention into effect, the cellulose derivative solution is applied I by. spreading or the like by any suitable means, for instance a doctor knife, on one side of each thickness of fabric to be combined, and if desired 'more than one coat may be applied, in which case the fabric to which the first coat has been applied may be dried off before the application of the second coat. The fabricsare then passed through pressing rollers with the undried coated sides in contact. The cementing solution may also be applied at the nip between the pressing rollers. In some cases a single application of the solution to the untreated thicknesses of fabric may be sufficient.

As the precipitating material, we may usea dilute acid bath; for instance, a bath of dilute acetic, sulphuric, hydrochloric or phosphoricacid, but solutions of salts, such as sodium silicate, or acid vapours may also be used, for instance solulimited by the following examples, in which the parts are by weight:

Example 1 Two pieces of bleached calico were spread on one side with one coat each of a 7% solution of glycol cellulose (made by the method described in U. S. Patent No. 2,036,257) in 7.5% sodium hydroxide solution. The filtered solution had a viscosity of 26 c. g. s. units at 20 C. The pieces were dried in the usual manner, and a second coat of the same solution was spread on to the same side of each and the pieces were doubled in a doubling machine. After being dried at a raised temperature the material was introduced into a bath of 3% sulphuric acid, after which it was very thoroughly washed and dried. The material so prepared showed excellent adhesion between the layers and withstood prolonged boiling in a solution of one part soap and one part anhydrous sodium carbonate per parts of solution.

Example 2 Two pieces of bleached calico were spread, each on one side, with a single coat'of a 7% solution of glycol cellulose made as described in Example 1, but having a viscosity of 76 c. g. s. units. The pieces of cloth were then doubled together and were introduced into an acid coagulating bath without preliminary drying. The material was then dried and finished.

Example 3 A piece of woven poplin was coated with a 7% solution of glycol cellulose (prepared by the combination of one quarter molecular proportion of ethylene oxide with soda cellulose) having a viscosity of c. g. s. units. A piece of open-mesh interlayer material was simultaneously coated with the solution and pressed on the coated surface of the poplin. The uncoated side of the interlayer material and one side of a second piece of woven poplin were coated with the solution and pressed into contact. The three-ply fabric was then led through a coagulating bath of 3% sulphuric acid, and thoroughlywashed and dried. The fabric so produced was suitable for the manufacture of collars, cuffs, shirt fronts and the like.

If in Example 1, a 7% solution of methyl or,

ethyl cellulose or a 5% solution of cellulose phosphate or sulphate were used instead of the 7% solution of glycol cellulose a similar result would be obtained.

The coagulation of the cellulose may be asslated or obtained by the use of heat, for instance the sheets after being pressed together might be passed over a steam heated drum before, or as part of, the process of being dried, or the heat of drying may be raised considerably above the usual temperature, 1. e., to a temperature of above 70 0.; or the rollers which press the sheets together may be heated.

In the manufacture of material for the manufacture of shirt collars, cuffs and the like the material is conveniently made by use of the ln-' vention into a 3-ply material consisting of two layers of shirting with an interlayer of a coarser material such as shrunk sheetlngs having the weight of 2.5 ozs. per square yard and a pick of 40 x 36 or having the weight of 3.2 ozs. per square yard and a pick of 60 x 71. 1

Among the various advantages of this invention is that the coagulation appears to take place in a discontinuous film which is permeable to air and'moisture. I As many apparently widely different embodimentsof this invention may be made without departing from the spirit-and the scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims, wherein ployment of one or other of the processes described in U. S. Patents Nos. 2,036,257 and 2,046,- 174.

We claim:

1. A process for the manufacture of laminated material comprising a plurality of fabric layers which comprises coating at least one of the fabrics with an alkaline solution of a cellulose derivative, placing the surfaces to be joined in contact with each other, applying pressure thereto,

and subsequently treating with a coagulating agent to precipitate the cellulose derivative, washing and drying.

2. A process as claimed in claim 1, wherein the cellulose derivative is a cellulose ether with a low degree of etherification.:

3. A process as claimed in claim 1, wherein the cellulose. derivative is an alkyl cellulose with. a low degree of etherification.

- 4. A process as claimed in, claim 1, wherein the cellulose derivative is a glycol cellulose with a low degree of etherification.

ROBERT REEKIE HOWDEN BROWN. JAMES MARCHBANKS COOPER. f 

